/**
 * OpenRouter AI Service Provider
 * 
 * Provides unified integration with OpenRouter API for streaming roleplay dialogue,
 * real-time clinical supervision, scenario generation, and vocal speech synthesis/transcription.
 */

import { Message, Scenario, AnalysisResult } from '../types';
import { getOpenRouterApiKey, DEFAULT_OPENROUTER_MODEL, DEFAULT_SUPERVISOR_MODEL } from './apiConfig';
import { SYSTEM_ANALYSIS_PROMPT, SYSTEM_SUMMARY_ANALYSIS_PROMPT } from '../constants';

const OPENROUTER_BASE_URL = 'https://openrouter.ai/api/v1';

export interface OpenRouterOptions {
  model?: string;
  temperature?: number;
  maxTokens?: number;
  apiKey?: string;
}

export interface StreamChatCallbacks {
  onChunk: (chunkText: string) => void;
  onComplete?: (fullText: string) => void;
  onError?: (error: any) => void;
}

/**
 * Streams roleplay chat completion from OpenRouter using Server-Sent Events (SSE).
 */
export async function streamOpenRouterChat(
  messages: Message[],
  systemInstruction: string,
  callbacks: StreamChatCallbacks,
  options: OpenRouterOptions = {}
): Promise<string> {
  const apiKey = getOpenRouterApiKey(options.apiKey);
  if (!apiKey) {
    const error = new Error("OpenRouter API key is missing. Please set your OpenRouter API Key in Settings.");
    callbacks.onError?.(error);
    throw error;
  }

  const model = options.model || DEFAULT_OPENROUTER_MODEL;

  const formattedMessages = [
    { role: 'system', content: systemInstruction },
    ...messages.map(m => ({
      role: m.role === 'model' ? 'assistant' : m.role,
      content: m.text
    }))
  ];

  try {
    const response = await fetch(`${OPENROUTER_BASE_URL}/chat/completions`, {
      method: 'POST',
      headers: {
        'Authorization': `Bearer ${apiKey}`,
        'Content-Type': 'application/json',
        'HTTP-Referer': 'https://cognitive-clarity.app',
        'X-Title': 'Cognitive Clarity'
      },
      body: JSON.stringify({
        model,
        messages: formattedMessages,
        temperature: options.temperature ?? 0.7,
        max_tokens: options.maxTokens ?? 1200,
        stream: true
      })
    });

    if (!response.ok) {
      const errorText = await response.text();
      throw new Error(`OpenRouter API error (${response.status}): ${errorText}`);
    }

    const reader = response.body?.getReader();
    if (!reader) throw new Error("Unable to read response stream.");

    const decoder = new TextDecoder('utf-8');
    let fullText = '';
    let buffer = '';

    while (true) {
      const { done, value } = await reader.read();
      if (done) break;

      buffer += decoder.decode(value, { stream: true });
      const lines = buffer.split('\n');
      buffer = lines.pop() || '';

      for (const line of lines) {
        const trimmed = line.trim();
        if (!trimmed || trimmed.startsWith(':')) continue;
        if (trimmed === 'data: [DONE]') continue;

        if (trimmed.startsWith('data: ')) {
          try {
            const data = JSON.parse(trimmed.substring(6));
            const delta = data.choices?.[0]?.delta?.content || '';
            if (delta) {
              fullText += delta;
              callbacks.onChunk(delta);
            }
          } catch (e) {
            // Partial JSON buffer ignored
          }
        }
      }
    }

    callbacks.onComplete?.(fullText);
    return fullText;
  } catch (err) {
    callbacks.onError?.(err);
    throw err;
  }
}

/**
 * Executes a single-turn structured CBT turn analysis via OpenRouter JSON mode.
 */
export async function analyzeTurnWithOpenRouter(
  turnContext: string,
  scenarioTitle: string,
  scenarioDescription: string,
  cbtFocus: string[],
  options: OpenRouterOptions = {}
): Promise<AnalysisResult> {
  const apiKey = getOpenRouterApiKey(options.apiKey);
  if (!apiKey) {
    throw new Error("OpenRouter API key is missing. Please set your API key in Settings.");
  }

  const model = options.model || DEFAULT_SUPERVISOR_MODEL;

  const systemPrompt = `${SYSTEM_ANALYSIS_PROMPT}
SCENARIO CONTEXT:
Title: ${scenarioTitle}
Description: ${scenarioDescription}
CBT Focus Areas: ${cbtFocus.join(', ')}

[OUTPUT REQUIREMENTS]
Return ONLY a valid JSON object matching this schema:
{
  "analysis": {
    "distortions": ["string"],
    "isAdaptive": boolean,
    "evidence": "string"
  },
  "rating": {
    "score": number (1-5),
    "reason": "string"
  },
  "suggestions": {
    "alternativeThought": "string",
    "behavioralStep": "string"
  }
}`;

  const response = await fetch(`${OPENROUTER_BASE_URL}/chat/completions`, {
    method: 'POST',
    headers: {
      'Authorization': `Bearer ${apiKey}`,
      'Content-Type': 'application/json',
      'HTTP-Referer': 'https://cognitive-clarity.app',
      'X-Title': 'Cognitive Clarity'
    },
    body: JSON.stringify({
      model,
      messages: [
        { role: 'system', content: systemPrompt },
        { role: 'user', content: turnContext }
      ],
      response_format: { type: 'json_object' },
      temperature: 0.2
    })
  });

  if (!response.ok) {
    const errorText = await response.text();
    throw new Error(`OpenRouter Clinical Analysis failed (${response.status}): ${errorText}`);
  }

  const data = await response.json();
  const rawContent = data.choices?.[0]?.message?.content || '{}';
  return JSON.parse(rawContent) as AnalysisResult;
}

/**
 * Generates a comprehensive post-session summary report via OpenRouter JSON mode.
 */
export async function generateSessionSummaryReport(
  messages: Message[],
  scenarioTitle: string,
  scenarioDescription: string,
  options: OpenRouterOptions = {}
): Promise<AnalysisResult> {
  const apiKey = getOpenRouterApiKey(options.apiKey);
  if (!apiKey) {
    throw new Error("OpenRouter API key is missing.");
  }

  const model = options.model || DEFAULT_SUPERVISOR_MODEL;
  const transcriptText = messages.map(m => `[${m.role.toUpperCase()}]: ${m.text}`).join('\n');

  const systemPrompt = `${SYSTEM_SUMMARY_ANALYSIS_PROMPT}
SCENARIO CONTEXT: ${scenarioTitle} - ${scenarioDescription}

[OUTPUT REQUIREMENTS]
Return ONLY a valid JSON object conforming exactly to this schema:
{
  "analysis": {
    "distortions": ["string"],
    "isAdaptive": boolean,
    "evidence": "string"
  },
  "rating": {
    "score": number (1-5),
    "reason": "string"
  },
  "suggestions": {
    "alternativeThought": "string",
    "behavioralStep": "string"
  }
}`;

  const response = await fetch(`${OPENROUTER_BASE_URL}/chat/completions`, {
    method: 'POST',
    headers: {
      'Authorization': `Bearer ${apiKey}`,
      'Content-Type': 'application/json',
      'HTTP-Referer': 'https://cognitive-clarity.app',
      'X-Title': 'Cognitive Clarity'
    },
    body: JSON.stringify({
      model,
      messages: [
        { role: 'system', content: systemPrompt },
        { role: 'user', content: `SESSION TRANSCRIPT:\n${transcriptText}` }
      ],
      response_format: { type: 'json_object' },
      temperature: 0.2
    })
  });

  if (!response.ok) {
    const errText = await response.text();
    throw new Error(`OpenRouter summary analysis failed (${response.status}): ${errText}`);
  }

  const data = await response.json();
  const rawContent = data.choices?.[0]?.message?.content || '{}';
  return JSON.parse(rawContent) as AnalysisResult;
}

/**
 * Generates a new validated CBT roleplay scenario via OpenRouter JSON mode.
 */
export async function generateScenarioWithOpenRouter(
  prompt: string,
  selectedConcepts: string[],
  difficulty: Scenario['difficulty'],
  options: OpenRouterOptions = {}
): Promise<Scenario> {
  const apiKey = getOpenRouterApiKey(options.apiKey);
  if (!apiKey) {
    throw new Error("OpenRouter API key is missing. Please enter your key in Settings.");
  }

  const model = options.model || DEFAULT_OPENROUTER_MODEL;
  const selectedContext = selectedConcepts.length > 0
    ? `Focus specifically on these CBT concepts: ${selectedConcepts.join(', ')}.`
    : '';

  const systemInstruction = `
    [CONTEXT]
    You are a Clinical CBT Scenario Architect.
    The user requires a structured clinical simulation designed to address specific cognitive distortions and behavioral challenges.
    Clinical Focus: ${selectedContext}
    
    [TASK]
    Transform the user's prompt into a cohesive, structured clinical scenario that sets up a targeted roleplay environment.
    
    [CONSTRAINTS]
    - CATEGORIZATION: You MUST categorize the scenario into one of: 'Social Anxiety', 'Workplace', 'Relationships', 'Self-Talk'.
    - DIFFICULTY CALIBRATION: The requested difficulty is '${difficulty}'.
      - 'Beginner': Low stakes, high support, clear-cut distortions, AI character is cooperative.
      - 'Intermediate': Ambiguous stakes, moderate social friction, subtle distortions, AI character has specific needs.
      - 'Advanced': High emotional triggers, persistent clinical resistance, complex cognitive patterns.
    - INTERNAL LOGIC: Provide a detailed "INTERNAL CBT LOGIC" section instructing the AI character how to react to the user's progress or cognitive lapses during the future roleplay.
    - CHARACTER VOICE: Define a realistic, emotionally consistent voice profile.
    
    [OUTPUT REQUIREMENTS]
    Return ONLY a valid JSON object matching this schema:
    {
      "id": "string",
      "title": "string",
      "characterName": "string",
      "description": "string",
      "category": "Social Anxiety" | "Workplace" | "Relationships" | "Self-Talk",
      "difficulty": "Beginner" | "Intermediate" | "Advanced",
      "systemInstruction": "string",
      "initialMessage": "string",
      "cbtFocus": ["string"]
    }
  `;

  const response = await fetch(`${OPENROUTER_BASE_URL}/chat/completions`, {
    method: 'POST',
    headers: {
      'Authorization': `Bearer ${apiKey}`,
      'Content-Type': 'application/json',
      'HTTP-Referer': 'https://cognitive-clarity.app',
      'X-Title': 'Cognitive Clarity'
    },
    body: JSON.stringify({
      model,
      messages: [
        { role: 'system', content: systemInstruction },
        { role: 'user', content: `Generate a clinical scenario for: ${prompt || 'A scenario exploring the chosen CBT concepts.'}` }
      ],
      response_format: { type: 'json_object' },
      temperature: 0.7
    })
  });

  if (!response.ok) {
    const errorText = await response.text();
    throw new Error(`OpenRouter scenario generation failed (${response.status}): ${errorText}`);
  }

  const data = await response.json();
  const rawContent = data.choices?.[0]?.message?.content || '{}';
  return JSON.parse(rawContent) as Scenario;
}

/**
 * Synthesizes spoken audio from text using OpenRouter's speech endpoint.
 */
export async function synthesizeSpeechWithOpenRouter(
  text: string,
  voice = 'alloy',
  apiKey?: string
): Promise<ArrayBuffer> {
  const effectiveKey = getOpenRouterApiKey(apiKey);
  if (!effectiveKey) {
    throw new Error("OpenRouter API key is missing.");
  }

  const response = await fetch(`${OPENROUTER_BASE_URL}/audio/speech`, {
    method: 'POST',
    headers: {
      'Authorization': `Bearer ${effectiveKey}`,
      'Content-Type': 'application/json',
      'HTTP-Referer': 'https://cognitive-clarity.app',
      'X-Title': 'Cognitive Clarity'
    },
    body: JSON.stringify({
      model: 'openai/tts-1',
      input: text,
      voice: voice
    })
  });

  if (!response.ok) {
    throw new Error(`OpenRouter TTS synthesis failed with status ${response.status}`);
  }

  return await response.arrayBuffer();
}